Terminal strip assembly and method of making it



May 5, 1959 L. J. MOELLER TERMINAL STRIP ASSEMBLY AND METHOD OF MAKINGIT Filed Sept. 1, 1954 INVENTOR. L. J MOE L (.51?

BY A 7'7'ORNEV TERMINAL STRIP ASSEMBLY AND NIETHOD OF MAKING IT LowellJ. Mueller, Towson, Md., assignor to Western Electric 'Company,Incorporated, New York, N.Y., a corporation of New York ApplicationSeptember 1, 1954, Serial No. 453,526

11 Claims. (Cl. 339-198) This invention relates to assemblies andmethods of making them, and particularly to terminal assembhes andmethods of making them.

Terminal strips are used in the telephone industry to facilitate thewiring of relay racks and other telephone apparatus assemblies requiringa multiplicity of circuit connections. One type of terminal stripconsists of a :body or block of insulating cast resin having embeddedtherein a plurality of terminals comprising elongated rods ofnoncircular cross section, preferably square rods. An electricalconnection suitable for use with such a tenthnal may comprise a wrappedelectrical connection, such as disclosed in United States Patent2,759,166, issued to Rudolph F. Mallina on August 14, 1956. Theterminals are arranged in a number of rows each comprising apredetermined number of spaced terminals with the ends of the individualterminals projecting from opposite ends of the cast resin block.

Previously, it has been a standard practice to assemble the terminalsindividually by hand in intricate steel molds which held them in theirproper positions. The molds were then filled with liquid casting resinwhich was then cured to form a rigid block around the intermediateportions of the terminals. The high initial cost of such molds and thelabor required to load them made it desirable to provide an assembly inwhich the 'pluralities of terminals are prepositioned and held securelyin the proper spaced relationship. The casting resin then may be moldedaround this assembly to form a finished terminal strip.

It is an object of this invention to provide new and improvedassemblies, and methods of making them.

It is another object of this invention to provide new and improvedterminal assemblies and methods of making them.

An assembly illustrating certain features of the invention may include aing a plurality of spaced noncircular apertures formed therein, and aplurality of elongated rods of noncircular cross sections made of astiff but resilient material and received within the apertures formed inthe spaced plates, the rods being placed by the walls of said aperturesunder torsional stresses of such magnitude as to lock the plates androds into a rigid assembly.

A method of making an assembly of a plurality of plates havingnoncircular apertures formed therein, and a plurality of elongated rodsof noncircular cross sections made of a stiff but resilient material,which illustrates certain features of the invention, may includepositioning the apertnred plates with apertures therein in alignment,inserting the rods :throngh the aligned apertures in the plates, andthen subjecting of such magnitude as to lock the plates and rods into arigid assembly.

.A complete understanding of the invention may be had om the followingdetailed description of a terminal strip assembly and a method .ofmaking the same conplurality of spaced plates, each hav- I the rods totorsional stresses distance such 2,885,651 Patented May 5, 1959 in adifferent position and illustrating another step in the method of makingthe assembly, and

Fig. 4 is an enlarged, fragmentary section taken along line 4-4 of Fig.2.

Referring now to Fig. 1, there is shown a completed, cage-like assembly10 which includes a pair of generally rectangular-shaped end plates 11and 12 formed from a stifi plastic material, such as polystyrene, or thelike.

Each of the end plates 11 and 12 is provided with three rows of fourequally spaced apertures 14-14 and 15-15. The apertures 14-14 are squarein cross section, and are designed to receive closely a plurality ofelongated, rodlike terminals 16-16 and 17-17 made of hard drawn brasswire, or the like, which is capable of being twisted axially andretaining a twisted set. The terminals 16-16 and 17-17, like theapertures 14-14 and 15-15 in which they are received, are square incross section and fit snugly in those apertures.

The end plates '11 and '12 are identical and the positions of theapertures 14 14 formed in the end plate 11 correspond exactly with thepositions of the apertures 15-15 in the end plate 12. In the completedassembly the end plates 11 and 1-2 are spaced apart 'a predeterminedthat the opposite ends of the terminals 1616 and -17-17 extend apredetermined distance beyond the o posite faces 'of the plates. Sincethe square apertures 14-14 and 15--'15 formed in the spaced end plates11 and 12, respectively, are designed to match, the terminals 16-16 and1717, when received therein, are positioned in substantially parallelrelationship with respect to each other.

Priod to the assembly of the end plates 11 and 12 and the terminals 1616and 17-17 to form the cagelike assembly 10, the terminals areindividually provided with predetermined axial pretwists. To each of theterminals 16- 16 there is imparted a clockwise axial pretwist set, asviewed from the forward end in Fig. 2, of approximately 8 per inch.Similarly a counterclockwise axial pretwist set of the same magnitude isimparted to each of the terminals 17--17.

In assembling the components to form the assembly 10, the end plates 11and 12 are brought closely together, one on top of the other, as shownin Fig. 2, with their corresponding square apertures 14--14 and 1515 inprecise matching relationsh'p. Equal numbers of the pretwisted terminals16-16 and 1717 are then inserted through the pairs of aligned apertures1414 and 15-15 in the matching end plates 11 and 12. For the purpose ofsimplifying the loading operation, the two apertures 1414 and 1515 atthe right hand side of each row of apertures in the end plates 11 and 12receive the terminals 1616 which are provided with a clockwise axialpretwist. The remaining apertures 1414 and 15- 15 receive the terminals1717 having a counterclockwise axial pretwist. Thus, six of the matchingpairs of apertures 1414 in the end plates 11 and 12 receive terrninalshaving a clockwise axial pret'wis't and the other six receive terminalspretwisted in the opposite direction. As shown in Fig. 4, each of theapertures l t-14 and I5-'-15 of the end plates 11 and 12 is provided onone face with a tapered enlargement to facilitate the insertion of theterminals 16-46 and 17 -47 therein.

The .final step in the assembly been inserted in all of jthe end platesmay be made the pairsof matching apertures 14-14 and 15-15 in accordancewith the above-described arrangement, consists of separating the endplates 11 and 12 to obtain the predetermined spacing therebetween. Asthe end plates are moved apart, the pretwisted terminals 16-16 and 17-17are prevented from rotating axially relative to the sides of theirassociated, closely fitting, square apertures 14-14 and 15-15 in the endplates. Consequently, as the end plates are separated, each of theterminals is twisted axially in a direction opposite to the direction ofits respective axial pretwist. The portions of the terminals 16-16 and17-17 between the spaced end plates 11 and 12 are untwisted to theextent that there is sub- 'stantially no twist remaining in them.However, due to the resilient properties of the pretwisted terminals16-16 and 17-17, resultant torques are set up in the individualterminals tending to return the same to their pretwisted condition.

Since the directions of the resultant torques depend solely upon thedirection of the pretwist in a particular terminal, the terminals 16-16exert torques tending to rotate the end plate 11 in a clockwisedirection, as viewed in Fig. 3, and the terminals 17-17 exertsubstantially equal torques tending to rotate the end plate 11 in theopposite direction. The pretwisted terminals 16-16 and 17-17 affect theend plate 12 in a similar manner. Since the resultant torques aresubstantially balanced, the total eflect is that the terminals 16-16 and17-17 andthe end plates 11 and 12 are locked securely in predeterminedpositions relative to each other to form a rigid, self-containing,cage-like assembly 10. The action of each terminal by way of analogymight be likened to a torsion spring subjected to a torsion load.

To separate the end plates 11 and 12 in the final step of the assemblyoperation a certain amount of force is required depending upon thenumber of terminals in the completed assembly. Since work must beexpended in untwisting each of the terminals, the amount of forceincreases directly with the number of terminals. For convenience inillustrating and describing the invention, the assembly has only twelveterminals. In actual practice assemblies having more than fortyterminals have been made in accordance with the teachings of theinminals which are of circular cross section.

The pretwisting step provides the rods 16-16 and 17-17 with spirated, orcorkscrew-like, portions running ,along their lengths in oppositedirections, which provision enables the oppositely-acting, lockingtorques to be set up in the rods when the rods and plates are mutuallyengaged followed by relative movement between the plates to change thespacing between the plates.

It will be understood also that the invention is not limited to thematerials described in connection with the foregoing exemplaryembodiment thereof. Manifestly,

a plastic, provided such material is capable of resisting thedeformation of the sides of the apertures formed .therein when actedupon by the resultant torques set up by the terminals held in torsion.However, in the assembly heretofore described, which is to be used inmale .ing a finished terminal strip, it is desirable that the endplatesbelmadeof an insulating plastic which is comalong the axes of therods at the spirated portions thereof 1 from a material other thanpati-ble with the casting resin and will adhere to it to insure a goodbond between the end plates and the resin. Likewise, in nonelectricalapplications, where it is not necessary to have conductive terminals,the metal terminals might be replaced by rods of any suitable materialhaving the requisite resilient properties and capable of retaining thenecessary pretwist set.

What is claimed is:

1. An assembly which comprises a pair of spaced plates having aplurality of spaced apertures formed therein, and a pair of elongatedrods made of a stiff but resilient material and pretwisted axially inopposite directions, each of said rods being received at itsoppositeends within apertures formed in the spaced plates with the portionthereof between said plates untwisted axially and held in torsion by thewalls of the apertures, whereby resultant torques are set up in the rodswhich efiectively lock the plates and rods together.

2. An assembly which comprises a plurality ofelongated rods made of astiff but resilient material having a noncircular cross section, some ofsaid rods being provided with an axial pretwist of one hand and theremaining rods having an axial pretwist of the opposite hand, a pair ofspaced plates having formed therein pluralities of noncircular apertureswithin which the opposite ends of said pretwisted rods are received, theportions of said rods between the spaced plates being untwisted axiallyand restrained from returning to their pretwisted sets by the walls ofthe apertures, whereby resultant, oppositelyacting torques are set up inthe rods which effectively lock the plates and rods together.

axial pretwist of the opposite hand, and a pair of spaced platesprovided with a plurality of noncircular apertures designed to receivethe rods and prevent them from tuming axially therewithin, saidpretwisted rods being received within corresponding pairs of alignedapertures in the spaced plates with the portions of the rods extendingbetween the plates untwisted axially and restrained from returning totheir normal pretwisted sets by the walls of the apertures, wherebyresultant, substantially equal and oppositely-acting axial torques setup in the rods effectively lock the plates and rods together.

4. A terminal strip assembly which comprises a plurality of elongatedterminals having generally rectangular cross sections and made of astiff but resilient, electrically conductive metal, one half of theterminals having been provided with a predetermined clockwise axialpretwist and the remainder having a counterclockwise axial pretwist ofequal magnitude, and a pair of spaced endplates made of an electricalinsulating material provided with a plurality of generally rectangularapertures designed to closely receive the terminals and prevent themfrom turning axially therewithin, said pretwisted terminals beingreceived within corresponding pairs of aligned apertures in the spacedendplates and having the intermediate portions thereof extending betweenthe endplates untwisted axially and restrained from returning to theirnormal pretwistedsets by the walls of the apertures, whereby theresultant, substantially equal and oppositely-acting axial torques setup within the terminals efiectively lock the endplates and terminalstogether.

5 A terminal strip assembly which comprises a plurality of elongatedterminals having generally rectangular cross sections and made of astiff but resilient metal, one ,half of. the terminals having beenprovided with a pre' determined clockwise axial pretwist and theremainder having'a' counterclockwise axial pretwist of equal magnitude,and'a pair of spaced plastic endplates provided with -a plurality ofequally spaced, generally rectangular apertures designed to closelyreceive the terminals and prevent them from turning axially therewithin,said pretwisted terminals being received within corresponding pairs ofaligned apertures in the spaced endplates and having the intermediateportions thereof extending between the endplates untwisted axially andrestrained from returning to their normal pretwisted sets by the wallsof the apertures, whereby the resultant, substantially equal andoppositely-acting axial torques set up within the terminals efiectivelylock the endplates and terminals together.

6. The method of making an assembly of a pair of plates having matchingnoncircular apertures therein and a pair ofelongated rods of noncircularcross sections made of a stifi but resilient material, which comprisespositioning the apertured plates in close proximity with the aperturestherein in alignment, imparting predetermined axial pretwists to therods in opposite directions, inserting the pretwisted rods through thealigned apertures in the plates, and separating the plates through apredetermined distance, whereby the portions of said pretwisted rodsextending between the spaced plates are untwisted axially and held intorsion by the walls of the apertures to set up resultant,oppositely-acting torques in the rods, which efiectively lock the platesand rods together.

7. The method of making an assembly of a pair of plates having aplurality of matching noncircular apertures formed therein and aplurality of elongated rods of noncircular cross sections made of astifi but resilient material, which comprises positioning the aperturedplates in close proximity with the apertures therein in alignment,imparting predetermined axial pretwists in one direction tosubstantially one half of the rods, imparting axial pretwist ofsubstantially the same magnitude in the opposite direction to theremainder of the rods, inserting the pretwisted rods through the alignedapertures in the plates, and separating the plates through apredetermined distance, whereby the portions of said pretwisted rodsextending between the spaced plates are untwisted axially and held intorsion by the walls of the apertures to set up within the rodsresultant, oppositely-acting torques which effectively lock the platesand rods together.

8. The method of making an assembly of a pair of plates and a pair ofelongated rods of noncircular cross sections made of a still? butresilient material, which comprises providing each plate with a pair ofnoncircular apertures adapted to receive the rods and to prevent themfrom turning axially therein, positioning the apertured plates in closeproximity with the apertures therein in alignment, impartingpredetermined axial pretwist to the rods in opposite directions,inserting the pretwisted rods through the aligned apertures in theplates, and separating the plates through a predetermined distance,whereby the intermediate portions of said pretwisted rods extendingbetween the spaced plates are untwisted axially and held in torsion bythe walls of the apertures to set up resultant, oppositely-actingtorques in the rods, which lock the plates and rods together.

9. The method of making an assembly of a pair of plates having aplurality of matching noncircular apertures formed therein and aplurality of elongated rods of noncircular cross sections made of astifi but resilient material, some of said rods having a permanent axialpretwist in one direction and the remainder having a permanent axialpretwist in the opposite direction, which comprises positioning theapertured plates in close proximity with the apertures therein inopposing positions in which the apertures are aligned, inserting thepretwisted rods through the aligned apertures in the plates, and separatin g the plates through a predetermined distance, whereby theportions of said pretwisted rods extending between the spaced plates areuntwisted axially and held in torsion by the walls of the apertures toset up within the rods resultant, oppositely-acting torques whicheffectively lock the plates and rods together.

10. The method of making an assembly of a plurality of plates havingnoncircular apertures therein, and a plurality of elongated rods made ofa stiflf but resilient material and having noncircular cross sectionsdesigned for close reception within corresponding apertures in theplates, which comprises imparting predetermined axial pretwists in onedirection to certain of the rods and in 0pposite direction to theremaining rods, mutually engaging the pretwisted rods and the plates sothat the rods extend between the plates and are received within thecorresponding apertures in the plates, and causing relative movementbetween the plates along the axes of the rods to change the spacingtherebetween so that resultant, oppositelyacting torques are set up inthe rods which are directed against the material of the plates definingthe apertures for effectively locking the plates and rods together.

11. The method of making an assembly of a plurality of plates havingnoncircular apertures therein, and a plurality of elongated rods made ofa stiff but resilient material and of noncircular cross section designedfor close reception within corresponding apertures in the plates, whichcomprises providing certain ones of the rods with spirated portionsrunning along their lengths in one direction and the remainder of therods with spirated portions running in the opposite direction, mutuallyengaging the rods and the plates so that the rods extend between theplates and are received within the corresponding apertures in theplates, and causing relative movement between the plates along the axesof the rods at the spirated portions thereof to change the spacingbetween the plates so that resultant, oppositely-acting torques are setup in the rods which are directed against the material of the platesdefining the apertures for efiectively locking the plates and rodstogether.

References Cited in the file of this patent UNITED STATES PATENTS1,750,039 Feltes Mar. 11, 1930 1,808,040 Hyatt June 2, 1931 1,917,573Black July 11, 1933 1,977,299 Bates Oct. 16, 1934 2,405,180 Blattner etal. Aug. 6, 1946 2,420,842 Schymik May 20, 1947

